A mobile communication system, such as a mobile phone system or a wireless local area network (LAN), is widely utilized at the moment. For example, 3rd Generation Partnership Project (3GPP) serving as a standard-setting organization completes or reviews a standardization of a communication specification, such as Long Term Evolution (LTE) or LTE-Advanced (LTE-A).
Along with the spread of smart phones and the like in the mobile communication system of these days, not only voice communications but also various services, such as video streaming, browser, global positioning system (GPS) location information, and credit settlement, are provided. In the mobile communication system, more important information including privacy information, such as the GPS location information and credit information, than other information may also be communicated. On the other hand, the communication traffic amount in the mobile communication system is significantly increased as compared with a previous era, with the use of streaming, browser, and the like.
In the above-mentioned mobile communication system, a protocol called Security Architecture for the Internet Protocol (IPsec) may be used in some cases. The IPsec is a protocol that provides a data alteration proof and a confidential function by using a cryptographic technology for each IP packet, for example.
The IPsec is utilized, for example, by combining plural protocols including an authentication mechanism and data security guarantee based on an authentication header (AH), a security protocol such as a data encryption based on Encapsulated Security Payload (ESP), a key exchange protocol such as Internet Key Exchange Protocol (IKE), and the like, with each other.
For example, with the utilization of the IPsec in the mobile communication system, spying and alteration of the privacy information, the credit information, and the like in the middle of a communication path may be avoided, and the security of the communication path may be secured.
The above-mentioned encryption processing based on the IPsec may be conducted by hardware such as dedicated-use large scale integration (LSI) in some cases. Since the encryption processing is conducted by the hardware, it is possible to increase the speed of the processing, for example, as compared with the processing conducted by software such as a central processing unit (CPU).
Meanwhile, the following technology related to the encryption processing is proposed, for example. That is, a data communication apparatus in which a cryptographic algorithm, such as high speed hardware processing or low speed software processing, is selected on the basis of a battery remaining amount, a communication expectation time notified by communication application, a cryptographic strength, and the like, is proposed. According to this technology, for example, a communication security and a communication duration of a portable device may be secured.
See RFC 4301 “Security Architecture for the Internet Protocol”, RFC 4303 “IP Encapsulating Security Payload (ESP)”, and RFC 4306 “Internet Key Exchange (IKEv2) Protocol”.
See also Japanese Laid-open Patent Publication No. 2005-117232.